The semiconducting nature of conjugated polymers are of great interest for a variety of organic applications such as organic field-effect transistors (OFETs). To be viable for real applications such as flexible displays, a major focus has been on enhancing charge carrier mobility. Significant advances have been made in the molecular design of conjugated polymers, which have yielded improved electronic properties and crystalline morphologies that further enhance carrier mobility.' Aligning conjugated polymers is a common route to enhance charge carrier mobility. A large number of techniques have been applied to obtain aligned films, which increases charger carrier mobility due to fewer grain boundaries and higher intrachain charge transport.2-19 Some of these methods include a rubbed polyimide surface as an alignment layer,3,20 directional crystallization,10,21 high temperature rubbing,18,19 and flow-coating methods.11,14,17 
One group has proposed an alternative method of alignment where films are coated on substrates with uniaxial nanogrooves.22-24 Simply rubbing the substrate with a diamond lapping paper generates the nanogrooves, which are approximately 100 nm in width and few nm in depth. To coat films on the nanogrooved substrates, this group developed a “sandwich casting” method.' Regioregular PCDTPT,25 which is a donor-acceptor copolymer of a cyclopenta[2,1-b:3,4-b′]dithiophene (CDT) donor unit and a [1,2,5]thiadiazolo[3,4-c]pyridine (PT) acceptor unit, was cast using the “sandwich casting” method to yield highly aligned films with high field-effect mobility23,24 (e.g. at least 20 cm2/V·s). The resulting films are semicrystalline and form long fiber-like bundle structures, which are preferentially aligned along the nanogrooves.23 The main-chain axis of the polymer (i.e. the direction along the length of the conjugated polymer chain axis) is parallel to the long-axis of the fiber while the π-π stacking direction is along the short-axis of the fiber, thus allowing for efficient intrachain and interchain charge transport.23 Although the sandwich casting method yields macroscopically aligned films with high field-effect mobility, the long casting time (˜8 hrs)24 is not practical to scale-up for the large-scale manufacturing needs of the “plastic electronics” industry. Therefore, a more industrial applicable method of forming aligned semiconducting polymer films, such as PCDTPT thin films, on uniaxial nanogrooved substrates is needed.